The present invention relates to the field of vehicle devices, and, more particularly, to a tracking and alerting system for a vehicle.
Motor vehicles, such as passenger cars, trucks, busses, fleet vehicles, etc. are widely used and knowing the locations of such vehicles is often desired. For example, should a vehicle be stolen, it would be beneficial to know the vehicle""s location so that authorities could be promptly and accurately directed to retrieve the vehicle. Indeed, the tracking system could plot the getaway path of the thief.
For a company with hired drivers, it may be desirable to know the driver""s whereabouts during the course of the day. Similarly, a rental car agency or other fleet operator, for example, may wish to know the whereabouts of its fleet of vehicles.
It may also be desirable to track the location of a vehicle as it is used throughout the course of a normal day. For parents of younger or older drivers, for example, knowledge of the vehicle""s location may provide some assurance that the driver is at designated locations and following a prescribed route.
A number of patents disclose various systems and approaches to tracking vehicles. For example, U.S. Pat. No. 5,223,844 discloses a tracking system including a control center and a mobile unit installed in the vehicle. The mobile unit may send security warnings to the command center via a wireless transceiver. Position information for the vehicle is determined using a GPS receiver at the vehicle.
U.S. Pat. No. 5,515,043 discloses a similar system which may send one or more preprogrammed telephone messages to a user when away from the vehicle. The user may remotely access location information or cause certain commands to be carried out by entering a personal identification number (PIN).
The widespread availability and use of the Internet has prompted a number of vehicle tracking systems to also make use of the Internet. For example, TelEvoke, Inc. proposed such a system in combination with Clifford Electronics. The system was to provide notification, control and tracking services via the telephone or the Internet. Users could be notified via phone, e-mail, or pager of events such as a car alarm being triggered. Users could control the vehicle remote devices via phone, web, or PDA such as unlocking car doors. Additionally, users could track TelEvoke-enabled vehicles on the Internet or via the telephone. An Internet map could be viewed by the user showing the actual and prior vehicle locations. TelEvoke offered its services via a centralized fully automated Network Operations Center. To reduce the communications costs, it was proposed to use the control channel of the cellular telephone network.
Many conventional vehicle tracking units include many input and output connections. Accordingly, such units may be difficult to install in a vehicle. This is especially so since the space available to access and connect to vehicle wires is likely to be restricted. Accordingly, errors in the initial installation may occur. Accurate diagnosis of any such errors may be time consuming and add further to the installation costs. Maintenance of an installed system may also be complicated if each connection must be individually checked and rechecked.
Some conventional vehicle tracking units also include a power down or sleep mode in which the cellular receiver is turned off to lower the power draw on the vehicle battery, but the GPS receiver and controller are still active to determine vehicle position information and monitor the vehicle sensors. These vehicle tracking units typically go into this power down mode a predetermined time after the vehicle ignition turns off, e.g., 48 hours. Yet, this may be problematic in that vehicles with older or weakened batteries will have inadequate power to start the vehicle in 48 hours.
As such, some such vehicle tracking units when in power down mode turn on the cellular receiver only for a predetermined period and at predetermined time increments, such as for five minutes at the top of every hour. While this approach may conserve battery power, it may nonetheless be inconvenient for a user to only have a small window every hour in which he can send commands to the vehicle tracking unit.
In view of the foregoing background, it is therefore an object of the present invention to provide a vehicle tracking unit with enhanced battery power conservation features and related methods.
This and other objects, features, and advantages in accordance with the present invention are provided by a vehicle tracking unit for a vehicle of a type including a vehicle battery and at least one vehicle security device. The vehicle tracking unit may include a vehicle position determining device, a wireless communications device for communicating with a monitoring station and including a receiver and a transmitter, a back-up battery, and a battery sensing circuit for sensing a voltage of at least one of the back-up battery and the vehicle battery. Furthermore, the vehicle tracking unit may also include a security device detection circuit for the at least one vehicle security device, a controller cooperating with the wireless communications device, the security device detection circuit, and the vehicle position determining device for sending position and security signals to the monitoring station.
In addition, the controller may also be connected to the battery sensing circuit for enabling operation of the receiver based upon the sensed battery voltage being above a threshold, and for disabling operation of the receiver based upon the sensed battery voltage being below the threshold. Also, operation of the transmitter may be enabled irrespective of the sensed battery voltage. Thus, the controller will advantageously allow the receiver, which may consume a significant amount of battery power, to remain on as long as possible while preserving enough battery power to allow the vehicle to be started (i.e., when the vehicle battery is supplying power) and/or to allow other components of the vehicle tracking unit to function properly.
More particularly, the receiver when enabled may operate substantially continuously, and the transmitter when enabled may operate substantially intermittently based upon the security device detection circuit. Further, the controller may enable operation of the receiver based upon the sensed battery voltage being above the threshold for a predetermined duration. By way of example, the threshold may be greater than about 11.5 Volts, although other values may also be used.
In addition, the controller may also enable operation of the vehicle position determining device based upon the sensed battery voltage being above the threshold and disable operation of the position determining device based upon the sensed battery voltage being below the threshold. In particular, the controller may enable operation of the vehicle position determining device based upon the sensed battery voltage being above the threshold for a predetermined duration. The controller may also cooperate with the wireless communications device to send a low power message to the monitoring station based upon the sensed battery voltage being below the threshold.
By way of example, the vehicle position determining device may be a Global Positioning System (GPS) device, and the wireless communications device may be a cellular telephone communications device. Furthermore, the cellular telephone communications device may communicate over a cellular control channel.
A vehicle tracking method aspect of the invention is for a vehicle of a type including a vehicle battery, at least one vehicle security device, and a vehicle tracking unit, such as the one described briefly above. The method may include sensing a voltage of at least one of the vehicle battery and the back-up battery using the vehicle tracking unit, enabling operation of the receiver based upon the sensed battery voltage being above a threshold, disabling operation of the receiver based upon the sensed battery voltage being below the threshold, and enabling operation of the transmitter irrespective of the sensed battery voltage to allow sending of position and security signals to a monitoring station.